12/28/2015 10:42 pm ET Updated Dec 28, 2016

Concussions: Could Women Have Increased Risk?

With the topic receiving big screen exposure, concussions are being discussed nearly daily in the news, from broadcast networks and newspapers to professional journals and magazines. The causative factors of long-term cognitive deficits in football players, hockey players and fighters are being researched, published and discussed at conferences. We now know that some of football's legends have experienced sad and tragic ends to their lives, and these outcomes are being at least partially attributed to repetitive head trauma.

Yet, what about girls and women in sports? Do they suffer the same rate of concussion as boys and men in similar sports? The answer may surprise you. Girls and women appear to have an even higher concussion rate in the same sport. Girls in softball (vs. baseball), basketball and soccer have reportedly incurred nearly double the concussion rate of boys (Lincoln AE, et. al. Am J Sports med 2011).

The primary theory for the increased concussion rates for girls is that girls have greater head-neck acceleration when exposed to external force (Tierney RT, et. al. Med Sci Sports Exerc 2005). This head-neck acceleration is sometimes named angular velocity. The reason behind this theory is that the neck muscle mass and strength of females is less than that of their male athlete counterparts, which prevents head velocity from trauma to be slowed effectively. If two male soccer players collide, their heads and necks will move slower than those of two females in the same situation.

The role of acceleration in concussion occurrence is hardly a new topic, as it was described in 1982 (Gennarelli TA, et. al. Ann Neurol 1982). And it has been determined that other factors, such as the direction of the major head acceleration, can have an impact on concussion rates as well.

The latest consensus in research was reached during the 4th International Conference on Concussion in Sport, Zurich 2012. The findings at this conference acknowledged that being female may be a modifier and a possible increased risk for concussion (McCrory P, et. al. Br J Sports Med 2013).

Many sports fans don't realize, or recognize, that direct head trauma is not the only cause of concussions in athletes. Head-neck acceleration may cause the brain to impact against the cranium without head trauma. Here are the most common causes of concussions among the athletes in various sports:

  • Two players colliding, with or without direct head trauma;
  • A player's head hitting the ground if he/she falls;
  • A player being hit in the head by an opposing player's knee or foot once on the ground;
  • There is no consensus on heading with regard to head trauma yet, as there are articles implicating transient changes in cognitive function with head that refute this suggestion.
Basketball - Same as the above, as well as:
  • An impact to the head from another player when trying to rebound;
  • Falling backwards over another player and landing on the floor.
Baseball and Softball - Similar falling conditions above, as well as:
  • Direct head trauma from a ball (pitched or thrown to a base);
  • Direct head trauma from a line drive to the pitcher or base runner;
  • Collisions at bases and home plate.

While the male player can and does incur concussions with these scenarios, the female athlete, with less ability to slow head-neck acceleration, may be more susceptible.

With the world focused on the struggle to obtain a realistic and valid concussion rate among male football players, we may want to consider the results of one sobering survey when estimating how women might actually be impacted. This survey of high school football players revealed a reported concussion rate of 5.6%. A reported concussion was defined as a concussion that the coaches were aware of. Yet, when these same athletes were asked about symptoms after their respective seasons, there was a 65% concussion rate (Moreau WJ. American Chiropractic Board of Sports Physicians Sports Science Symposium, 2005, podium presentation).

We can certainly hypothesize similar errors and underestimation in determining the rate of concussions in female athletes, as well. So what might that staggering number be?